Electric headlamp more particularly for miners



Nov. 2 1926. 1,605,019

P. WOLF ELECTRIC HEADLAMP MORE PARTICULARLY FOR MINERS Filed June 9, 1925 Patented Nov. 2, 1926.

UNITED STATES PATENT @tfh'itih.

PAUL woLr, or ZWIGKAU, sum rainy.

Application filed June 9, 1925, Serial No. 35.963. and in Germany september 5, 1923.

This invention relates to electric headlamps more particularly intended for miners but not limited thereto. The electric head-lamps for miners which are in many respects to be preferred to the hand lamps have to comply with the safety rule that in the event of the bulb or the protecting glass window being destroyed the electric current has to be automatically interrupted in order to prevent the ignition of fire damp. Head-lamps as hitherto constructed comply with this rule in so far as the bulb when destroyed is pressed out of its stocket by a spring. However, this arrangement does not secure complete safety since its operation depends upon the complete destruction of the bulb. If the bulb is simply damaged without being destroyed along its full length it still offers a resist ance to the spring as before, the circuit re maining closed.

According to the present invention the automatic interruption of the current does not depend upon the destruction of the bulb or protecting window but upon an impact of a strength that would destroy the bulb or the protecting window. The invention consists inthe provision of an arrangement of a contact device which without the lamp breaking closes under the action of a sufficiently strong impact and short circuits the source of current thereby causing a fuse inserted in the circuit to melt. The fuse being arranged in a position inaccessible to the miner, the arrangement according to the present invention also prevents the miner from manipulating the extinguished lamp in such a manner as to produce sparks which would cause ignition of mine gases.

The invention may be carried into effect in different. ways. In the arrangement illustrated in the accompanying drawin s the lamp fitting consisting of the reflector and lamp socket, bulb and protecting lens is movable relatively to the casing against a braking resistance and the short circuit effected by the pressing of the lamp fitting into the casing by an impact upon the protecting window or its frame. The braking resistance may consist of a spring or a friction brake may be used instead of the spring, or the resistance of an air cushion provided behind the lamp fitting which acts as a piston.

The form of construction first above referred to has been illustrated, by way of example, in the accompanying drawing in which,

Figure 1 illustrates in section a lamp pro vided on the head covering A,

Figure 2, a waist belt carrying the accun'iulators B also in section, and

Figure 3 is a diagram of the electrical connections.

The lamp is Jrovided in front of the. head covering A. and is connected with the accu mulator B by means of a tow-core cable C. The casing D is provided at its front end with a ring 1 in which the annular frame 2 of the lens 3 acting as a protecting window is mounted through the interposition of a soft insulating material (soft rubber rings) in such a manner as to have sutficient play to more. .a parabolic reflector 4 fits into the annular frame 2 which reflector is provided with a socket 5 to receive the bulb 6. The one pole of the battery is connected at 7 to the metallic reflector whilst the other pole thereof is connected to a spring 8 which is provided on the end contact of the fitting of the lamp. The braking resistance which is in the form of a spring 9 is mounted on the reflector through the intermediary of an insulating layer, the movable contact consistingof a pin 10 which is electrically connected with the reflector. lVhen the lamp fitting ispressed into the casing D, the pin 10 touches the casing which is already connected to one pole of the battery at 8 thereby causing a short circuit to be produced and the fuse 11 to melt. As will be seen from Figure 2, this fuse is provided on the inner side of the cover 12 of the accumulator and is thus inaccessible to the miner.

lit is to be understood that the braking resistance acting against the closure of the contact has to be dimensioned in such a way that, so far as shaking and ordinary impacts are concerned, which generally occur in the use of the lamp without damaging the bulb or protecting window, the contactcannot be closed, the latter taking place only in the case of strong impacts.

In the form of construction illustrated in the drawing, owing to the small distance between the current carrying parts D and 4; metallic contact and a short circuit will be produced also when the casing D is substantially deformed by impacts which do not come direct from the front of the lamp.

What I claim is An electric head-lamp for miners comprising in combination, a lamp casing, a reflector, means for insulating said casing from said reflector, a lamp socket secured to said reflector, electrical connections for said lamp means for forcing said reflector towards the front of said. casing, and a projection on the rear of said reflector in prox imity to said casing, said projection being adapted to contact said casing upon rearward movement of the reflector to shunt said electrical connections.

In testimony whereof I have signed my name to this specificationl PAUL WOLF. 

